Yes you can, but not in the same window. The only way to do this, at present, is to open a second instance of PicoScope 6.

For example, open the first one. This one will communicate with your scope and be the live view. Then open a second instance. This one will not communicate with the hardware because it is already in use. Select a demo device instead. Now open up your saved capture in the second instance of Pico 6 and size your two Pico 6 windows to suit.